Interrelations of markers of pubertal development and adolescent adjustment and behavior are investigated at three times of measurement, six months apart, in a sample of 9- to 14-year-old boys and girls. The markers of pubertal development include serum hormone levels, pubertal stage (Tanner criteria), and age. Menstrual history data also were collected for the girls. Psychological assessment of the adolescent include adolescent- and parent-report of behavior problems and competencies and behavioral observations. Overlap of hormone levels for pre- and post-menarcheal girls as well as overlap of hormone levels for the various days of the menstrual cycle for menarcheal girls indicate that, in research on biobehavioral processes, menarche should be conceptualized as part of a maturational process rather than as a developmental marker. Self-reported menstrual history data indicate that "phase of the cycle" for newly menarcheal adolescents needs to be reconceptualized. Additionally, a perturbation hypothesis for hormone-behavior relations was put to a conservative replication test, using hormone factor scores and behavior composites at three times of measurement. The perturbation hypothesis was supported, and most findings replicated (i.e., were similar at two or three times of measurement): for boys, higher adrenal axis hormones were associated with a higher degree of problems involving irritability and attitudinal problems and higher gonadal axis hormones were associated with higher degrees of problems in academic performance; for girls, higher gonadal axis hormones were associated with higher degrees of affective problems and peer as well as family relationship problems. There also were chronological age and time of maturation findings for boys and pubertal stage findings for girls.